The invention described herein may be manufactured and used by or for the Government of the United States of America for government purposes without the payment of any royalties therefor.
The invention relates in general to methods of deploying sonobuoys and in particular to methods of deploying sonobuoys to encircle a target, such as a submarine.
Aircrews need an easy- to- use tool for determining where and when to deploy sonobouys such that a contact, such as a submarine, is encircled. The aircrew has information concerning submarine contact location relative to the aircraft, the error associated with that contact location, the sonobouy detection radius, the aircraft speed and the submarine""s estimated speed. What is needed is way to determine: 1) how many sonobouys are needed to accomplish the encirclement protocol; 2) how long and what distance will be flown to accomplish the protocol; and 3) the course and flight times for each sonobouy drop.
In one prior method, the aircrew estimates the largest circular area within which the submarine may be. This is done with pencil and paper. The buoys are then dropped by aircrew estimate. The aircrew continuously adjusts their estimate of the position uncertainty of the submarine to estimate where and when they will drop the buoys. This method is difficult to use because the pencil and paper calculations are performed while the helicopter is flying very low over the water and requires the aircrew to divert their attention from the outside situation. Another limitation of the prior method is that all the computations are estimates. The aircrew easily may find themselves dropping the buoys only to discover at a very late time that they do not have enough sonobouys to complete the encirclement protocol.
The invention is a method for deploying sonobouys that includes the use of a computer. The computer may be a hand held computer or a computer that is part of the deploying aircraft computer system. The deploying aircraft""s cruise speed and the sonobuoy detection radius are input into the computer. When the submarine contact is made, the aircrew inputs into the computer the position of the submarine relative to the aircraft (range) and the submarine estimated speed.
When the computer is instructed to xe2x80x9crunxe2x80x9d, a computer display shows the number of sonobouys to be used, the flight time to the first sonobouy drop, and the total time and flight distance to be used to accomplish the encirclement protocol. An important advantage of the invention is that the aircrew can decide whether or not to continue the encirclement tactic while traveling to the first bouy drop. When the computer is instructed to xe2x80x9crunxe2x80x9d again, the computer display shows the course and flight times to the second, third, and remaining sonobuoy drops.
The inventive method can be accomplished by one aircrewman, without diverting attention of the pilot from flying duties. In addition, the method yields a definitive answer to the key question of how many sonobuoys are needed. The invention quickly yields definitive answers rather than estimates. Furthermore, the invention contributes to improved flight safety by avoiding xe2x80x9ceyes in the cockpitxe2x80x9d over a prolonged time.